Meanwhile, the crew, Kitty Stryker and Courtney Trouble, set up the lights and the cameras.

They settle on a storyline so implausible it smacks of self-parody, something about a woman hiring a male prostitute only to have Darling and the other man show up at once. The lights and cameras click on, and the clothes come off.

This group were some of the more than 250 porn performers, filmmakers, fans and academic researchers who convened in Toronto last month for an international gathering of feminist pornographers.

At an awards show and an academic conference at the University of Toronto, they celebrated achievements in the small but growing genre - and debated what it means for their porn to be feminist.

"If it's possible to have sex in a feminist way, it's possible to record it in a feminist way," says Pandora Blake, a 29-year-old London-based sex worker, pornographer and porn performer.

Image caption
Carlyle Jensen wants to promote porn she can recommend to her female customers

In recent years, feminist porn producers and performers have settled on a rough agreement on how to shoot pornography that empowers rather than demeans women and depicts authentic female sexuality rather than the presumed fantasies of the stereotypical straight man.

Image caption
Ms Naughty, left, flew in from Australia, while Jennifer Lyon Bell came from Amsterdam

Among other things, feminist pornographers say they give the performers significant input in the kind of sex they have on screen and encourage them genuinely to enjoy themselves.

"Performers can negotiate what kind of safer sex practices they want to do, whether its dams or condoms or gloves, what kind of sexual activities they're prepared to do, they can choose their scene partners," says Stardust, a tall, tanned and buxom Australian who is studying for a doctoral degree at the University of New South Wales.

Aesthetically, feminist porn dispenses with many of the tropes of mainstream straight porn - the primacy of the male climax, the portrayal of women as sex objects dedicated to the pleasure of the male partner, the "male gaze" camera angles that linger on the prone female body while disembodying the penis.

"You get to see more of people's bodies, more of people's faces, and there's less of an assumption of one person or one gender being the focus over another," says Tristan Taormino, a leading feminist pornographer, author and organiser of the Feminist Porn Conference at the University of Toronto.

Feminist porn - an oxymoron?

Image copyrightJulia Long

"When I was researching my book Anti-Porn: The Resurgence of Anti-Pornography Feminism, I spoke to lots of young feminists. When I asked them about 'feminist porn', most of them thought the term risible, like saying 'I'm a vegetarian carnivore'," writes Julia Long.

"I find the idea that 'feminist porn' is qualitatively different fairly spurious. The producers make all kinds of claims around body diversity, the use of the camera, etcetera. But to me the films look like variations on a theme.

"'Feminist porn' legitimises the production of pornography, but these films are consumed by a tiny minority of people. It's a distraction from the debate about mainstream pornography, which perpetuates narratives that normalise violence against women and girls.

"We're seeing the term 'feminist' applied to more and more things and it is becoming meaningless. We have to remind ourselves that feminism is not about getting an award for 'hottest gonzo sex scene'. It is a serious political movement and its concern is social transformation and liberation from patriarchy."

"An essential part of women's liberation in general is sexual liberation," she says.

"Making any kind of pornography that genuinely arouses women and gets them off is important to women's liberation. That's part of why these films are feminist - it's a feminist enterprise to show women's pleasure."

Feminist porn is political - men, women, transgender people, gays, lesbians, self-identified "queer" people, straight people, disabled people, people of colour, fat people - all are filmed on their own terms and express their own sexuality, industry figures say.

"It's a place where people with alternative sexualities can explore their sexualities," says Carey Gray, a transgender man, pornographer and owner of a leather goods business.

"Trans-guys can look at me in performance and feel validated about their own bodies."

HM Anderson, a 41-year-old South Carolina mother of two, describes her affinity for feminist porn as a matter of taste.

"I just find mainstream porn to be very boring," she says. "It's just old. You're just like, 'jeez, really, that's what you think women do in bed?'"

But the feminist pornographers "let me be me" - and give her much more say over what she does with her body in front of the cameras.

"If I'm not comfortable with something I'm not afraid to say no," she says. "I don't have to worry about never getting hired again."

The feminist porn audience is different from that of mainstream porn, too - it comprises straight and gay couples, straight and gay women, transgender people and "queer" people who reject the common categories of gender and sexuality - and comparatively few solo straight men.

Image caption
Hudson prepares for the shoot, the first he had ever done with a woman and a transgender person

Feminist pornographers are almost all women - only three of the 19 filmmakers honoured at the awards ceremony this year are "cisgender" men - lending a sense that the feminist porn community is turning away from the studio patriarchy that runs mainstream porn.

Whether it's a movement, a genre, an aesthetic, or all of the above, feminist porn took off in the last decade, helped along by the rise of the internet and the decline in the cost of digital film production.

"The internet has democratised porn in a big way," says Blake, who that morning shot a solo spanking scene with Ms Naughty, the Australian founder of BrightDesire.com. "It's empowered a lot of performers to produce their own content - it's empowering performers, which means its empowering women."

Image caption
Tristan Taormino, far left with her partner Colten, is one of the leading filmmakers in the feminist porn genre

The Feminist Porn Awards were established by the owner of a female-oriented Toronto sex shop who realised her customers wanted to see pornography, just not the mainstream stuff they found to be fake, robotic, emotionally vapid, and visually repetitive, and perhaps demeaning to women.

Carlyle Jensen says her customers at Good for Her found the narrow range of sexual practices and imagery they saw in porn unappealing, and they wanted something they could feel good about watching.

So she started stocking more of the newly emerging feminist porn films - and in 2006 launched the annual awards show to promote the work.

"It's not about excluding anybody, it's about bringing everybody else into it, representing everybody who hasn't traditionally been there. If you still want to watch young, straight, white, thin people having sex in the missionary position, that's great. We're just expanding it a bit more."

One night in April, the ninth Feminist Porn Awards show was held at a theatre in north Toronto before dozens of porn stars of very shape, size, colour and gender, as well as fans, producers, and a handful of journalists.

Darling wore a dark suit with a red shirt, black braces and white bowtie. He has a smooth, soft face, crew-cut hair, a ring through his septum and metal plugs like miniature car rims in his ear lobes.

Hudson was dressed rocker-style in a white T-shirt with sleeves rolled up to show off his tattoos, blue jeans, thick eyeliner and full mutton-chop whiskers. A Dominican-American native of New York City's gritty Bronx borough, he got into pornography after answering a Craigslist advert.

Image caption
Pandora Blake, left, and Ms Naughty say the internet has enabled them to reach a niche audience

He shoots both mainstream pornography and the feminist type. The mainstream gigs pay better, but the "niche" feminist porn is more "personal".

"It's more reflective of me," he says.

Prizes are awarded in categories such as "Steamiest Straight Movie", "Smutty Schoolteacher Award for Sex Education", "Best Boygasm" and "Most Tantalising Trans Film". Stardust is named Hearthrob of the Year, while Trouble wins "Hottest Dyke Film" for her work Lesbian Curves 2: Hard Femme.

At the end of the show, Darling, Hudson, Stardust, Stryker and Trouble pile into a pair of cabs and head back to the hotel.

The performers are tired - they are accustomed to shooting mornings, when their bodies are fresh. But with Stardust in from Sydney and all of them gathered in town for the awards and conference, the grist was ready for the mill.

When the filming ends 90 minutes later, the hotel room is redolent with the smell of sweaty, post-coital bodies and the clinical odour of latex.

The performers are thrilled with their sexual audacity - this was the first time Hudson had ever shot a woman-man-trans-man threesome.

Darling eases back onto the bed so Trouble can film a promotional clip.

"This was definitely one of the queerest shoots I've ever done," he says.